Fixes markdown for Usage readme section.

Author: dsposito

README.md

@@ -21,7 +21,7 @@ composer require dayrev/extractor
 
 Alternatively, add `"dayrev/extractor": "^1.0"` to your composer.json file.
 
-##Usage
+## Usage
 ```php
 $extractor = DayRev\Extractor\Provider::instance('embedly', ['api_key' => 'YOURKEYHERE']);
 $content = $extractor->extract('http://www.espn.com/espn/wire/_/section/ncf/id/18398497');